A secret plan for Navy SEALs to plant a listening device in North Korea in 2019 fell apart when they were spotted by fishermen.

For the operation, the military chose SEAL Team 6’s Red Squadron — the same unit that killed Osama bin Laden. The SEALs rehearsed for months, aware that every move needed to be perfect. But when they reached what they thought was a deserted shore that night, wearing black wet suits and night-vision goggles, the mission swiftly unraveled.

Two to three civilians on a North Korean fishing boat were believed to be unarmed and diving for shellfish, sources familiar with the mission said.